Physicist and novelist (Good Benito) Lightman brings his characteristic sense of wonder and awe to these concise discussions of the origins of the universe. Previously published in two collections of the 1980s (Time Travel and Papa Joe's Pipe and A Modern Day Yankee in a Connecticut Court), these 21 graceful essays combine examinations of how birds fly, theoretical underpinnings of time travel and the gravitational forces impinging on a ballerina, as well as snippets of scientific history--a profile of atomic physicist Niels Bohr, imaginary encounters with Isaac Newton and Thomas Edison--and autobiographical glimpses of Lightman's own scientific career. Several selections are parables or fables, for instance, his whimsical adventures in Ironland, where everything is made of iron, and an evocation of a Persian city whose denizens are unable to leave--a metaphor for how scientists construct or abandon theories. On a more serious note, Massachusetts Institute of Technology professor Lightman calls for more funding of pure research and explores how we blind ourselves to the dangers nuclear weapons pose to the Earth's survival. (Apr.)